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Biomedical subjects

J A Sykes

Publications and source records attributed to J A Sykes.

At least 19 recordsLinked to original sources
PubMed2003

Treatment of acute lymphoblastic leukemia-induced extreme hypercalcemia with pamidronate and calcitonin.

OBJECTIVE: To describe extreme hypercalcemia as the presenting feature of acute lymphoblastic leukemia in an 8-yr-old girl and the combined use of pamidronate and calcitonin for its treatment. DESIGN: Case report. SETTING: Pediatric intensive care unit. PATIENT: An 8-yr-old girl with 20.0 mg/dL serum calcium (reference range, 8.8-10.4 mg/dL) and 2.66 mmol/L ionized calcium (reference range, 1.13-1.32 mmol/L). INTERVENTION: Intravenous pamidronate and subcutaneous calcitonin. MEASUREMENTS AND MAIN RESULTS: Our patient presented with nausea, vomiting, lethargy, weight loss, fatigue, and weakness but, remarkably, did not exhibit electrocardiographic changes. Initial treatment with hydration at 8 mL x kg(-1) x hr(-1) and furosemide was ineffective. A single dose of 1 mg/kg intravenous pamidronate given over 24 hrs complemented by three doses of 5 units/kg subcutaneous calcitonin over 36 hrs lowered serum calcium to a normal range within 3 days. Side effects noted were hypocalcemia, hypomagnesemia, and hypophosphatemia. They were most pronounced 7-9 days after treatment, stabilized with supplementation, and returned to acceptable ranges by 1 month without need for ongoing electrolyte supplements. A renal computed tomographic scan did not show nephrocalcinosis. The patient remained free from recurrence of hypercalcemia 6 wks after initiating chemotherapy for acute lymphoblastic leukemia. CONCLUSIONS: Extreme hypercalcemia can be a presenting feature of acute lymphoblastic leukemia, but it may not result in life-threatening organ dysfunction. Combined treatment with pamidronate and calcitonin should be considered for treating hypercalcemia that does not respond to conventional therapy with hydration and furosemide.

Antineoplastic Agents↗
PubMed1990

High serum concentrations of aflatoxin in Nepal as measured by enzyme-linked immunosorbent serum assay.

1 Sera from 28 Nepalis, both patients and workers in a hospital in Banepa, Nepal were examined for AFB1 by enzyme-linked immunosorbent assay (ELISA). 2 This assay, previously validated using spiked sera, provides a sensitive rapid determination of serum aflatoxin (B1, G1 and Q1). 3 All 28 sera were positive with concentrations from 60 pg ml-1 to 10 ng ml-1. 4 These results suggest that consumption of aflatoxin in Nepal is high (greater than 50-800 ng kg-1 d-1). 5 No reports of the degree of contamination of food, human consumption or body fluid concentrations of aflatoxin in Nepal have been previously published. 6 Aflatoxin may contribute to the development of hepatocellular carcinoma, which is probably a common tumour in Nepal.

Aflatoxins↗
PubMed1983

Normal superoxide dismutase-1 (SOD-1) activity with deletion of chromosome band 21q21 supports localization of SOD-1 locus to 21q22.

The gene for superoxide dismutase-1 (SOD-1) is clearly on chromosome 21, although there is disagreement on the precise band location of SOD-1 on the long (q) arm of number 21. We report a patient with normal superoxide dismutase-1 (SOD-1) activity and an interstitial deletion of chromosome 21 resulting in monosomy for band q21. His phenotype is characterized by moderate mental retardation, a long narrow face, high and arched palate, cardiac murmur, undescended testes, and long hyperflexible extremities. The normal SOD-1 activity supports localization of this enzyme to 21q22.1.

Adolescent↗
PubMed1982

Plasma lactoferrin levels in pregnancy and cystic fibrosis.

Plasma lactoferrin levels were determined by radioimmunoassay for the different weeks of normal pregnancy, in normal healthy adults and in children with and without cystic fibrosis. The lactoferrin levels were higher in pregnancy than in both male and female normal adults and showed a slight progressive increase up to week 29 and thereafter remained high. Five our of seven children with cystic fibrosis had markedly raised plasma lactoferrin levels from six to 16 times higher than the mean of a control group of children.

Adolescent↗
PubMed1981

Modulation of protein expression in endometrial adenocarcinoma cells by in vitro exposure to estradiol and progesterone.

Protein maps of in vitro hormone-modulated adenocarcinoma cells from an endometrial tumor are described. It is noted that mapping of tumor tissues by means of the two-dimensional analysis described by O'Farrell and associates of 35S-methionine-labeled proteins can provide a characteristic map for each tumor and that the methionine-containing proteins of tumor cells can be independently modulated by the in vitro additions of estradiol and progesterone. Such protein modulation could be indicative of hormonal therapeutic responsiveness of individual endometrial adenocarcinomas and other hormone receptor-positive tumors. Tumor maps may further provide data for the identification and isolation of new tumor markers which might be correlated with the radiotherapeutic and chemotherapeutic sensitivity of the malignancy.

Adenocarcinoma↗
PubMed1980

Long-term incorporation of tritiated adenine into deoxyribonucleic acid and ribonucleic acid by Treponema pallidum (Nichols strain).

Treponema pallidum (Nichols strain), extracted in medium containing Eagle minimal essential medium 50% fresh, heat-inactivated normal rabbit serum, and 1.0 mM dithiothreitol, was incubated under 3% oxygen in the presence of tritiated nucleic acid precursors. [8-3H]adenine was incorporated with high efficiency into trichloroacetic acid-insoluble material; 2'-deoxyadenosine and uridine were incorporated in lower quantities, and thymine and thymidine were not incorporated. Incorporation of [3H]adenine was inhibited by penicillin G, mitomycin C, actinomycin D, and erythromycin, but was not affected by cycloheximide. Partial purification of nucleic acids from T. pallidum incubated with [8-3H]adenine for 36 to 72 h and subsequent treatment with ribonuclease and deoxyribonuclease revealed that 15 to 20% of the trichloroacetic acid-precipitable counts were resistant to ribonuclease but susceptible to deoxyribonuclease. A simple assay was developed in which NaOH treatment was used to distinguish incorporation into ribonucleic acid and deoxyribonucleic acid. Both ribonucleic acid and deoxyribonucleic acid synthesis continued for 6 days of incubation under 3% O2, whereas incorporation was limited to the first day of incubation in samples incubated under aerobic or anaerobic conditions. T. pallidum thus appears to be capable of significant de novo deoxyribonucleic acid and ribonucleic acid synthesis under microaerobic conditions.

Adenine↗
PubMed1979

The synthesis and release of prostaglandins by human urinary bladder muscle in vitro.

Using the technique of bioassay the presence, production, and importance of prostaglandins (PG) in human bladder muscle have been investigated in vitro. Low basal tissue levels of PG were shown. E series PGs were released by isolated bladder muscle strips in organ bath experiments. The spontaneous activity and PG release of these strips could be markedly reduced by the addition of indomethacin. Incubation of bladder muscle with the PG precursor, arachidonic acid, resulted in the synthesis of substantial quantities of PGs.

Arachidonic Acids↗
PubMed1978

Influence of oxygen tension, sulfhydryl compounds, and serum on the motility and virulence of Treponema pallidum (Nichols strain) in a cell-free system.

The motility and virulence of Treponema pallidum (Nichols strain) were monitored during incubation in a modified tissue culture medium to study the effects of oxygen tension and medium composition on survival of the organism. A basal medium of Eagle minimal essential medium with 50% fresh, heat-inactivated normal rabbit serum was used inasmuch as better survival occurred with 50% normal rabbit serum than with lower concentrations. Addition of 0.5 to 2.0 mM dithiothreitol or 2.0 mM dithioerythritol to the basal medium led to significantly longer retention of T. pallidum viability in the presence of 3% oxygen than under aerobic or anaerobic conditions. The results of this investigation lend support to the classification of T. pallidum as a microaerophilic organism and provide direction for the design of potentially successful culture systems, with or without tissue culture cells.

Blood↗
PubMed1978

A preliminary study of the superoxide dismutase content of some human tumors.

The cell cytosol superoxide dismutase (SODase) content of 46 human tumors was investigated. The extraction procedure of McCord and Fridovich was used with the epinephrine assay of Misra and Fridovich (J. Biol. Chem., 247; 3170-3175, 1975). The purpose of the study was to determine whether SODase could be reliably assayed from small, biopsy-sized pieces of tumor (0.5 to 1.0 g). In most cases it was possible to examined larger masses of tumor, which served as a control of the methodology. In this preliminary study SODase values, calculated from a standard curve derived from purified bovine blood SODase with a specific activity of 2584 units/mg, ranged from as little as 0.23 to as much as 160.5 units/g of tumor. These findings suggested that the procedures used might be feasable on a routine basis to determine the SODase content of tumors and its possible relationship to the radiation sensitivity of the tumors.

Breast Neoplasms↗
PubMed1977

Interaction of Treponema pallidum (Nichols strain) with cultured mammalian cells: effects of oxygen, reducing agents, serum supplements, and different cell types.

Cultured mammalian cells extend the time of survival of Treponema pallidum (Nichols strain). Various parameters that have been previously shown to enhance treponemal survival in vitro were examined for influences on the interaction of T. pallidum with cultured cells. With cells derived from normal rabbit testes, the time of retention of treponemal virulence was extended in an atmosphere containing reduced concentrations of oxygen. Glutathione and cysteine, when added to the basal tissue culture medium, prolonged treponemal survival. In an assessment of various tissue culture medium supplements, normal rabbit serum was equivalent to fetal bovine serum and superior to bovine serum albumin fraction V (BSA), fatty acid-poor BSA, and lipid-pooed for TRK-2, HSE, NRK, and C6 cells. Dithiotreitol, as an additional reducing agent, sharply enhanced treponemal survival. With SF1Ep NBL-11 cells and basal tissue culture medium containing glutathione, cysteine, and dithiothreitol, in an atmosphere of approximately 3% oxygen, T. pallidum was maintained without detectable decreases in the number of virulent organisms for 6 days.

Blood↗
PubMed1977

Characterization of the attachment of Treponema pallidum (Nichols strain) to cultured mammalian cells and the potential relationship of attachment to pathogenicity.

The interaction of Treponema pallidum (Nichols strain) with 19 different cultured mammalian cell types was examined. These types included cells derived from testis, kidney, spleen, lung, epidermis, cervix, urethra, and nerve tissue of human, rabbit, or rat origins. They represented normal and malignant cells, epithelial and fibroblastic morphology, cell lines, and cell strains, Large numbers of organisms attached to the cultured cells; this attachment prolonged the time of retention of active treponemal motility. Attachment was examined in terms of the number of treponemes inoculated, cultured cells present, and actively growing versus stationary cultured cells; the motility of the treponemes; the viability of the cultured cells; and the different cell passages. In sharp contrast to the attachment of T. pallidum, 11 nonpathogenic treponemes failed to attach to cultured cells. Immune syphilitic rabbit serum prevented the attachment of T. pallidum to cultured cells, as indicated by phase contrast microscopy and rabbit inoculations. This blockage of attachment by immune serum occurred without interfering with active motility of the organisms. Results are discussed in terms of the potential relationship of attachment to the pathogenicity of T pallidum.

Antibodies, Bacterial↗
PubMed1977

Scanning electron microscopy of Treponema pallidum (Nichols strain) attached to cultured mammalian cells.

This paper describes the attachment of Treponema pallidum (Nichols strain) to cultured mammalian cells as a visualized by scanning electron microscopy. Treponemes were incubated for 3 hr with cultured cells derived from normal rabbit testes or human skin epithelium, then fixed, processed with critical-point drying, and examined with a Cambridge Mark 2A scanning electron microscope. Large numbers of treponemes became attached to the cultured cells without altering the morphological integrity of the cultured cells. Attachment appeared to involve a very close physical proximity of treponemes to the cultured cells; at the site of attachment, no changes such as swelling or indentation of the cultured cell surface were observed. The addition of ruthenium red to the fixatives produced a treponemal-associated surface precipitate. This material, which is probably mucopolysaccharide and/or phospholipid, may be important in protecting the organisms against host defense mechanisms; in addition, it may be involved in the serological unresponsiveness of freshly prepared suspensions of T. pallidum.

Animals↗
PubMed1975

Intracellular Treponema pallidum in cells of a syphilitic lesion of the uterine cervix.

In an electron microscopic study of biopsy tissue from an ulcer of the human cervix uteri, organisms morphologically identical to T. pallidum were observed. Large numbers of the organisms were seen lying among collagen fibrils and between cells. T. pallidum was seen within vacuoles of some fibroblasts and epithelial cells. Within the nucleoplasm of several cells, treponemes were observed, surrounded by a clear zone which might represent a mucopolysaccharide outer layer. The siameter of the organisms was 171 nm., and the diameter of the external axial filaments was 25 nm., dimensions similar to those reported by others for T. pallidum.

Adult↗